Nintendo plans to release a new type of DS game card that works on all DS models, but will take advantage of DSi's hardware features.
Masato Kuwahara, the project leader of the DSi hardware group, confirmed that Nintendo is planning "Nintendo DSi enhanced game cards." These new types of game cards will be playable on all models of the DS. However, if these game cards are played on a DSi, players will be able to enjoy DSi hardware specific features, such as creating textures from photographs that are taken by the DSi camera.
The "Nintendo DSi enhanced game cards" are currently in development, and the development process of the DSi hardware inspired Nintendo to create these enhanced game cards.